将FindScanline汇编代码转换为purepascal
我试图将一些德尔福5代码转换为Delphi XE7-x64，我坚持下面的代码：
function FindScanline(Source : Pointer; MaxLen : Cardinal;
Value : Cardinal) : Cardinal; assembler;
asm
PUSH ECX
MOV ECX,EDX
MOV EDX,EDI
MOV EDI,EAX
POP EAX
REPE SCASB
MOV EAX,ECX
MOV EDI,EDX
end;
据我了解以下事情正在发生：
push the contents of ECX register(Value) onto the stack move contents of EDX register(MaxLen) into ECX register. now ECX holds (MaxLen) move contents of EDI register into EDX register. now EDX holds (EDI) move contents of EAX register into EDI register. now EDI holds (Source) pop ECX into EDX. now EDX holds (Value). Was (EDI) lost? repeat while equal ?decrement ECX for each char? move contents of ECX register into EAX register move contents of EDX register into EDI register
对于引用函数FindScanline用于函数GetCursorHeightMargin
任何帮助翻译上面将不胜感激。
这是一个直译：
function FindScanline(Source: Pointer; MaxLen: Cardinal; Value: Cardinal): Cardinal;
var
Ptr: PByte;
begin
Result := MaxLen;
if Result > 0 then
dec(Result);
Ptr := Source;
while (Result > 0) and (Ptr^ = Value) do
begin
inc(Ptr);
dec(Result);
end;
end;
处理边缘情况很不幸。
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